Storage structure



Sept. 12, 1967 E. G. DUERINGER STORAGE STRUCTURE Filed Aug. 2, 1965 AAJ u ugrr 7 INVENTOR. E. G. DUERINGER DONALD E. PORTE R United States Patent 3,340,658 STORAGE STRUCTURE Erwin G. Dueringer, 1025 W. Dean Road, River Hills, Wis. 53317 Filed Aug. 2, 1965, Ser. No. 476,345 5 Claims. (Cl. 52-246) This invention relates to a storage structure and more particularly to a storage structure for the storage of granular and flake materials, such as forage.

It is well-known in the art that, if air is entrapped between such material and the walls of the structure in which such material is stored, or in the material itself, the air causes the stored material to spoil because the oxygen in the air tends to promote mold growth and deterioration. Accordingly, storage structures ordinarily are constructed so as to be cylindrical in shape, in order to ensure that, when the structure is filled with such material, such material will compress and gain the mass required to urge the material to drop, due to the force of gravity, to the bottom of the structure and completely fill the structure and thereby inhibit the formation of air spaces. However, it has been found that, when a tall cylindrical structure (as, for example, a cylindrical structure having a wall height in excess of twenty-three feet) is filled to the top with such material, the weight of the stored material exerts substantial internal pressures against the wall of the lower portion of the structure, resulting in excessive circumferential stresses (commonly known as hoop stresses) in the wall which cause the wall to stretch and swell and thereby weaken the overall strength of the structure.

Various attempts to prevent such stretching and swelling have been made. For example, structural rings have been disposed circumferentially around the outer surface of the wall of the structure. Patent No. 2,920,810 issued Jan. 12, 1960', to the inventor shows a construction wherein such a ring is employed. However, the use of such rings necessitates that either the rings be constructed separate from the structure and bolted or otherwise fastened thereto or that, as is involved in the construction shown in such patent, additional forming operations be performed during the manufacture of the wall sections of the structure to make such rings integral with such wall sections, thereby adding to the expense of manufacturing the structure. 7

A few storage structures currently in use are constructed so as to have walls which taper from the bottom to the top of the structure. Such a structure is described in Patent No. 2,551,216 issued May 1, 1951. However, experience has shown that, during the filling of such a tapered structure, the increases in the diameter of the structure from the top to the bottom thereof tend to permit air spaces to form between the material and the wall of the structure and in the material itself; and such air spaces, particularly if they occur in material stored in storage structures which are not constructed so as to be airtight, cause the stored material to spoil.

The present invention provides an improved storage structure, in which the upper section of the structure is generally cylindrical in shape, and the lower section thereof has walls which taper so that the internal diameter of the bottom of such lower section exceeds the internal diameter of the bottom of such upper section by an amount in the range of two to 3.5 percent of the slant height of the lower section. A structure thereby is provided in which the upper section is constructed and shaped so as to compress material stored in the upper section and cause it to gain sufficient mass to urge such material to drop to the bottom of the structure and completely fill the structure. In addition, because of the shape and dimensions of the lower section of the structure, the

creation of excessive hoop stresses in the lower part of the wall of the structure is prevented, without permitting the formation of air spaces between the stored material and the wall of the lower section of the structure.

The best mode presently contemplated of carrying out the invention is illustrated in the accompanying drawings, in which:

FIGURE 1 is a perspective view of a storage structure embodying the present invention, with parts broken away and sectioned, in which the angle of the taper of the walls of the lower section of the structure has been shown in exaggerated form.

FIGURE 2 is a fragmentary, enlarged, vertical section taken through a joint between two overlapping curved wall sections of the structure.

FIGURE 3 is a top plan view of one tier of curved wall sections in the upper section of the structure.

FIGURE 4 is a fragmentary, enlarged, plan section taken through a joint between two of the overlapping curved wall sections shown in FIGURE 3.

The drawings illustrate a storage structure approximately forty feet in height, which rests on a foundation 1 and the wall of which is constructed of overlapping curved section 2 and 3 of fiber reinforced resin materials. It is contemplated that the present invention also is adapted for use with storage structures the walls of which are fabricated of overlapping curved sections of metal of suitable gauge and with structures the walls of which are constructed of a series of vertically super-imposed approximately cylindrical sections secured at their adjacent edges, which may be of metal or plastic or other suitable material.

As shown in the drawings, the wall of the structure is constructed of eight tiers of curved sections 2 and 3. Each such curved section 2 and 3 is approximately sixty inches in height, of which the upper approximately three inches overlap the lower approximately three inches of the curved section 2 or 3, as the case may be, immediately above it in order to provide wall surfaces which abut against one another when nuts 5- are threaded home on bolts 6. As a consequence, the overall wall height of the structure is approximately 456 inches. Similarly, ap proximately three inches of each curved section 2 or 3 overlaps approximately three inches of the curved section 2 or 3, as the case maybe, immediately counter-clockwise of. it, viewing the tier in which such curved sections 2 or 3 are located from the top of the structure, in order to provide wall surfaces which abut against one another when nuts 7 are threaded home on bolts 8.

Upper section of structure In order to provide a substantially cylindrical upper section 9 of the structure which will serve to compress the material stored in the storage structure and cause such material to gain mass, the five upper tiers of curved sections 2 are virtually identical as to height, length and radius of curvature. As shown in the drawings, each of such sections 2 is approximately 200 inches long, sixty inches high and from one-eighth to one-quarter of an inch thick, and the radius of curvature thereof is ten and one-half feet. As a consequence, the curved sections 2, when bolted together, form a substantially cylindrical wall for the upper section 9 of the structure; and the height of such upper section 9 is slightly in excess of twenty-three feet, which comprises approximately sixty percent of the wall height of the structure.

Lower structure In order to construct a tapered lower section 10 of the structure, with a wall having the desired angulation to avoid the formation of excessive hoop stresses therein without permitting air spaces to form between the wall 3 and the material stored in the structure, the bottom three tiers of curved sections 3, or approximately forty percent of the wall height of the structure, are constructed of sections 3 which are identical as to height and length to the curved sections 2 embodied in the upper section 9 of the structure, but the radius of curvature of the bottom edge of each such section 3 is approximately five-eighths of an inch larger than the radius of curvature of the bottom edge of the curved section 2 or 3, as the case may be, immediately above such curved section 3 (the thickness of such curved sections 3 is three-eighths of an inch to provide vertical strength for supporting upper section 9). As a result, the internal diameter of the bottom edge of the bottom or third tier of curved wall sections 3 of the lower section 10 is approximately one and one-quarter inches larger than the internal diameter of the bottom edge of the second tier of curved sections 3, and is approximately three and three-quarter inches larger than the internal diameter of the bottom edge of the bottom or fifth tier of curved sections 2 of the upper section 9 of the structure. Thus, the bottom three tiers of curved sections 3 form lower section 10 of the structure substantially in the shape of a frustum of a right circular cone, in which the diameter of the lower base of such frustum exceeds the diameter of the upper base thereof by an amount in the range of from two to 3.5 percent of the wall or slant height of such frustum. It has been found that substantially smaller rates of increase in the internal diameter of the lower section 10 do not alleviate the excessive hoop stresses caused by internal pressures against the walls of the lower section 10 due to the mass and weight of the material stored in the structure; and that substantially greater rates of increase in such diameter result in pockets of air forming between the material stored in the structure and the walls of lower section 10, causing spoilage of the stored material.

Thus the storage structure has the advantages of causing the material therein to be compressed and gain mass and thereby drop to the bottom of the structure due to the force of gravity and completely fill the structure and, at the same time, of eliminating the hoop stresses ordinarily formed in the walls of the lower portion of tall cylindrical structures, without permitting air spaces to form between the stored material and the structures walls, as occurs in structures having fully tapered walls.

Various modes for carrying out the invention are con templated as being within the scope of the following claims particularly pointing out and distinctly claiming the subject matter which is regarded as the invention.

I claim:

1. A storage structure, comprising a generally cylindrical upper section, and a lower section having tapering walls whereby the bottom internal diameter of said lower section exceeds the bottom internal diameter of said upper section by an amount in the range of two to 3.5 percent of the slant height of said lower section.

2. A storage structure, comprising a generally cylindrical upper section having a height comprising approximately sixty percent of the wall height of said structure, and a lower section having tapering walls whereby the bottom internal diameter of said lower section exceeds the bottom internal diameter of said upper section by an amount in the range of two to 3.5 percent of the slant height of said lower section.

3. A storage structure, comprising an upper section generally having the shape of a hollow right circular cylinder and a height comprising approximately sixty percent of the wall height of the structure, and a lower section generally having the shape of a hollow frustum of a right circular cone in which the diameter of the lower base of said frustum exceeds the diameter of the upper base of said frustum by an amount in the range of two to 3.5 percent of the slant height of said frustum.

4. A storage structure, comprising an upper section generally having the shape of a hollow right circular cylinder and a height in excess of twenty-three feet, and a lower section generally having the shape of a hollow frustum of a right circular cone in which the diameter of the lower base of said frustum exceeds the diameter of the upper base of said frustum by an amount in the range of two to 3.5 percent of the slant height of said frustum.

5. A storage structure, comprising an upper section generally having the shape of a hollow right circular cylinder and a height in excess of twenty-three feet, and a lower section generally having the shape of a hollow frustum of a right circular cone in which the diameter of said frustum increases from the upper base to the lower base thereof at the approximate rate of one and one-quarter inches for each approximately fifty-seven inches of slant height of said frustum.

References Cited UNITED STATES PATENTS 2,551,216 5/1951 Martin 52--197 2,752,640 7/1956 Mazur 52195 2,852,110 9/1958 Dueriuger 52-247 FOREIGN PATENTS 935,526 2/1948 France.

FRANK L. ABBOTT, Primary Examiner.

J. L. RIDGILL, Assistant Examiner. 

1. A STORAGE STRUCTURE, COMPRISING A GENERALLY CYLINDRICAL UPPER SECTION, AND A LOWER SECTION HAVING TAPERING WALLS WHEREBY THE BOTTOM INTERNAL DIAMETER OF SAID LOWER SECTION EXCEEDS THE BOTTOM INTERNAL DIAMETER OF SAID UPPER SECTION BY AN AMOUNT IN THE RANGE OF TWO TO 3.5 PERCENT OF THE SLANT HEIGHT OF SAID LOWER SECTION. 